In order to enhance the performance output, fuel economy and exhaust of gases and/or to aid miniaturization and weight reduction of an internal combustion engine, it is preferred to eliminate cylinder liners used in the cylinder bores of an aluminum cylinder block. As one technique to accomplish this, there has been used a spraying technique for forming a sprayed film made of an iron-based material on an inner surface of the aluminum cylinder bore (see, for example, Japanese Patent Application Laid-open (JP-A) No. 2006-291336).
A sprayed film is applied by rotationally moving a spraying gun in an axial direction of a cylinder bore. In order to prevent foreign matter such as oxide from being caught in the sprayed film, the application may be carried out while providing an airflow inside of the cylinder bore as disclosed in JP-A No. 2006-291336.